Process for the protection of metals



contact with the atmosphere.

Patented May 29, 1951 PROCESS FOR THE PROTECTION OF METALS Lucien Hemmerand Jean Balvay, Paris, France, assignors to Societe anonyme dite:Standard Francaise des Petroles, a corporation of France No Drawing.Application December 16, 1948, Serial No. 65,747. In France January 3,1948 Claims.

This invention relates to the preparation of anti-corrosion preparationsfor protecting metal surfaces against corrosion and particularlytoprevent rusting of articles or surfaces of ferrous metals.

It is well known that the tendency to rust is one of the greatdisadvantages in the use of ferrous metal appliances, and that it isespecially -so in humid climates and coastal areas because of the actionof chlorine and other reactive materials contained in the atmosphere.

In order to protect metal surfaces from rust, it is usually sufficientto isolate them from all In order to do this, lubricating oils may beused. If two pieces of polished steel are taken and one of them immersedentirely in lubricating oil and the other is simply coated with a thinfilm of oil, e. g., by rubbing with a pad impregnated with lubricatingoil, the plate entirely immersed is protected against rust for a verylong time, while the plate which has simply been coated With a thinlayer of oil becomes covered with rust after a very short exposure tothe air.

The efficiency of the protection of coatings of this general type hasbeen increased by mixing with mineral oils a petrolatum or a parafiinwhich gives a Vaseline-like product. The problem has not, however, beencompletely solved.

When a plate protected by a thin coating of oil, on which has beenplaced a few droplets of water, has been exposed to the air, at the endof a few days rust appears in the regions Where the droplets of oil wereplaced, even sometime after these have evaporated. This occurs becausethe films of oil are not strictly continuous,

in particul' r in the regions Where the drops of water were, whichpermits actual contact between the metal and the atmosphere. This iscaused, in. fact, by a preferential displacement of water for oil on thesurface of the metal, that is to say, the water has a greater afiinityfor the metal surface than the oil and in time displaces the oil on thesurface of the metal, at least in part.

In order to obtain an efficient protection of the metal, it is necessaryto reverse these conditions and increase the affinity of the oil for themetal surface to a point where it displaces water.

The present inventors have discovered that there are two groups ofcompounds which, when mixed, are capable of producing the desired conditions of preferential displacement of water by oil on the surface ofthe metal,

The first group of compounds comprises those which are soluble in theoils and insoluble in Water and which have also a great affinity for themetal surface. The compounds capable of fulfilling these conditions are:

(a) Natural fatty acids or synthetic fatty acids having more than 10carbon atoms per molecule, sulfonated fatty acids or alcohols,naphthenic acids, sulfo-naphthenic acids, e. g., such as those obtainedby the treatment of petroleum distillates with sulfuric acid, resinicacids (e. g., abietic acid, etc.) obtained from the distillation ofwood, resinous or oily residues from paper manufacture, alkyl benzene ornaphthalene, sulfonic acids obtained by synthesis, polyacids, such asadipic acid, sebacic acid, and the like.

Cresols extracted from wood tar, such as the thio-cresols, alkylphenols, mercaptans, or compounds corresponding to the formula I-ISR, Rbeing an aliphatic radical having more than 5 carbon atoms and which maybe substituted in the organic radical of these products, may contain oneor more of the substitution groups such as: O, OH, N, S, 00, CL, and thelike.

(1)) Polyvalent metal salts of the above acids such as salts of lead,copper, iron, tin, zinc, manganese, mercury, and the like, are' betteragents than the similar acids. These salts can be prepared by doubledecomposition or by direct action of the metal, or better still itsoxide, with the difierent acids, phenols, thio-phenols or mercaptans (ingeneral the basic salts react better than the acid salts).

(c) The ether salts corresponding to the acids indicated above, inparticular, to ether salts of higher alcohols and most particularly,polyalcohols of natural, animal or vegetable origin, such as, suintine,lanoline, spermaceti oil, spermaceti wax, beeswax, Chinese wax, and thelike, or of synthetic origin such as the ether salts of pentaerythritol,cholesterol, and the like.

((1) Amines and imines of higher molecular weight, having more than 6carbon atoms in the molecule, and their salts with the organic acidsmentioned above, such as heptadecylamine oleate, and the like, alkylpyridine bases and their homologues, such as cetyl pyridine, and thelike, and their salts with the organic acids indicated above, ammoniumbases and pyridinium bases having more than 10 carbon atoms in themolecule, and their salts with the organic acids mentioned above.

The second group of compounds comprises compounds superficially activevis-a-vis the water by having a sufiicient solubility in the oil. The

inventors have discovered that these are generally salts of bases suchas sodium, potassium, ammonium, lithium, calcium, quaternary ammoniumbases, oxonium, urea and imines, and the like with:

1. The different acids mentioned above.

2. Cresols and phenols or naphthols, alkylated or not, and theircorresponding thio compounds.

3. Mercaptans having more than 5 carbon atoms in the molecule.

The process according to the invention consists in mixing from 120% ofany one or more of the many compounds of each of these two groups with alubricating oil. In this manner there are obtained products possessinganti-rust properties greatly superior to those of the pure oils andequally superior to those obtained when using a mixture of the compoundsof only one category. A plurality of compounds of each category may alsobe employed.

The comparative efiiciency was determined by the following method:

Metallic plates 3 x 10 centimeters were perfectly polished by mechanicalmeans and coated with a thin film of the rust resisting oil product bytotal immersion in the oil product and pouring off the excess of the oilover a period of 6 hours. The plates thus covered with the oilyprotective coating were maintained in an etuve at 25 C. The true test ofcorrosion consists in immersing the plates for one hour in standardizedsynthetic sea water and then to expose to air for a constant temperaturefor one hour. This cycle is repeated for eight hours and finally theplates remain in contact with the air of the etuve for sixteen hours.The number of days necessary for each plate to be completely coveredwith rust is noted.

In order to explain more fully the present invention, the followingexamples are given but the invention obviously is not limited to them.

The use of a mixture of suintine (suint) and lanoline on the one handand sulfonate of soda on the other hand, being already known, these areused for comparative purposes.

First series of emampZes.Using a single compound from one of the group:

Plate 100% Products Used rust at the end of- Spindle Oil y 1 SpindleOil+5% lead sulionaphthenate... 10 Spindle Oil+5% suintine 2 SpindleOil+10% sodium sulfonaphthenate. 2

Spindle il+10% triethanolaminc stearatc Sp ndle Oil+% triethanolaminestearate. Sp ndle Oil+5% triethanolamine suintate. Spindle Oil+5%ammonium chlorostearate Second series of ewamples.Using a mixture of onecompound from each of the two groups mentioned:

Third series of examples.Use of a plurality of compounds from each ofthe two groups:

The oily base may comprise petroleum mineral oils or synthetic oilscovering all ranges of viscosities from spindle oils (very lightlubricating oils) up to cylinder oils. Mixtures of anti-rust oils, suchas those obtained from petroleum or parafiin to obtain products of aVaseline-like consistency may also be used which may, if desired,be'diluted with a solvent such as gasoline, white spirits, gas-oil, orother appropriate solvents.

Such mixtures can be utilized with advantage wherever it is necessary topreserve a surface of ferrous metal against rust.

In place of using a mineral oil as the oily base, a drying oil may alsobe used. In this manner, with the addition of pigments generallyemployed in paints, excellent anti-rust paints may be obtained.

Excellent industrial anti-rust oils, petrolatums, waxes, and ordinary orbituminous or tarry paints can thus be obtained by adding, during orafter manufacture, mixtures of from 0.1 to 20% by weight, based on thetotal composition, of one or more of the compounds of each of the twogroups mentioned above.

The invention has been described both in general terms and by way ofspecific examples. Various ingredients may be used and numerousmodifications of detail conforming to the spirit thereof, can beeffected without departure from the invention.

What is claimed is:

1. Composition according to claim 6 wherein said oily vehicle is alubricating oil.

2. Composition according to claim 6 wherein said oily vehicle comprisespetrolatum.

3. Composition according to claim 6 wherein said oily vehicle comprisesa drying oil.

4. A corrosion inhibiting composition consist-.

ing essentially of a mineral oil base vehicle containing 0.1 to 20% byweight of a metal sulfonaphthenate.

5. Composition according to claim 4 wherein said oily vehicle is alubricating oil.

6. A rust inhibiting composition consisting essentially of a mineral oilbase vehicle containing 0.1 to 20% by weight of at least one metalsulfonaphthenate selected from the groups which consist of lead andsodium sulfonaphthenates and 0.1 to 20% of a material selected from thegroup which consists of lanoline and suintine.

7. A rust inhibiting composition consisting essentially of a lightmineral base lubricating oil containing about 5% by weight of sodiumsulfonaphthenate and about 10% by weight of suintine, based on theweight of the total composition.

8. A rust inhibiting composition consisting essentially of a lightmineral base lubricating oil containing about 10% by weight, based onthe total composition, of sodium sulfonaphthenate and abo 5 of lanoli e.

5 9. Compositmn according to claim 8 to which is added about 2.5% oflead naphthenate.

10. Composition according to claim 8 to which is added about 2.5% oflead sulfonaphthenate.

LUCIEN HEMMER. JEAN BALVAY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date Lebo Dec. 12, 1939 Rocchini Nov.4, 1941 Irwin May 26, 1942 Farrington et a1 J an. 19, 1943 Cook et a1Nov. 9, 1943 Sharp Apr. 17, 1945 Kollen Mar. 25, 1947

6. A RUST INHIBITING COMPOSITION CONSISTING ESSENTIALLY OF A MINERAL OILBASE VEHICLE CONTAINING 0.1 TO 20% BY WEIGHT OF AT LEAST ONE METALSULFONAPHTHENATE SELECTED FROM THE GROUPS WHICH CONSIST OF LEAD ANDSODIUM SULFONAPHTHENATES AND 0.1 TO 20% OF A MATERIAL SELECTED FROM THEGROUP WHICH CONSISTS OF LANOLINE AND SUINTINE.